Buttonhole sewing machine



BUTTONHOLE SEWING MACHINE Filed Nov. 2, 1933 4 Sheets-Sheet 1 Fig.1.

\nvenToT. Cori A.Q.Grip- Nov. 12, 1935. A o, Gmp 2,020,779

BUTTONHOLE SEWING MACHINE Filed NOV. 2, 1933 4 Sheets-Sheet 2 Fig.2.

7 Fig.4. 4o '48 lnvenTor. Carl A.O. Grip I by%&

ATTys.

c. A. o. GRIP 2,020,779

BUTTONHOLE SEWING MACHINE Filed Nov. 2, 1953 4 Sheets-Sher, 5

lnvenTor. Carl A.O.Grip

- ATTys.

Patented Nov. 12, 1935 UNITED STATES BUTTONHOLE SEWING MACHINE Carl A. 0. Grip, Newtonville, Mass, assignor to The Reece Button Hole Machine Company, Boston, Mass., a corporation of Maine Application November 2, 1933, Serial No. 696,349

16 Claims.

This invention relates to buttonhole sewing machines and particularly to that type of buttonhole sewing machine having an under threadpull-off member mounted on the turret and operating to pull 01f a length of under thread preparatory to the cutting of the under thread and the stay cord at the end of the sewing operation.

Buttonhole sewing machines are commonly constructed so that when the sewing on the buttonhole has been completed the stitch-forming mechanism and the work-holding means are given a relative movement to separate the stitched buttonhole from the stitch-forming mechanism and to place said stitched buttonhole and the buttonhole cutter in proper relative position for cutting the buttonhole slit.

The work is held clamped in the work-holding means during this relative movement and while the buttonhole slit is being cut but is unclamped when the buttonhole-cutting operation is completed.

The turret, on which the under thread mechanism and throat plate are mounted, is usually mounted on the turret and which is actuated.

to pull a length of under thread through the throat plate by said reverse rotation of the turret. Where the under thread-pull-off is thus actuated by the reverse rotation of the turret a part or all of the operation of pulling the under thread through the throat plate occurs after the work has been unclamped.

It is one of the objects of my present invention to provide an improvement on the thread-pullofi device illustrated in my said patent by which the under thread willbe pulled through the throat plate while the work is still clamped in the workholding means and before the work is released, and I accomplish this object by providing means for actuating the thread-pull-oil arm from the main cam of the sewing machine as distinguished from operating it by the reverse rotation of the turret as in my above-mentioned Patent No. 1,985,854. In some buttonhole sewing machines the buttonhole slit is out after the stitching on the buttonhole has been completed and in such machines the cutting of the buttonhole slit occurs before the clamps are released so that the work is still held in the clamp during the buttonhole-cutting operation. The cutting of the buttonhole is commonly. done by means of a cutter cam element carried by the main cam. Hence during any buttonhole forming cycle there is an interval of time after the stitching has been completed during which the rotation of the main cam operates to cut the buttonhole slit and then 1 to unclamp the work. With my improvement I make use of the buttonhole-cutting movement of the main cam for pulling off the length of under thread, the thread pull-off being actuated from the main cam at the time that the latter is 5. actuating the buttonhole cutter.

In order to give an understanding of the invention I have illustrated in the drawings a selected embodiment thereof which will now be described after which the novel features will be pointed out in the appended claims.-

Fig. 1 is a side view of a portion of a buttonhole sewing machine embodying my invention;

Fig. 2 is a fragmentary sectional view showing the turret in plan view and showing the part of the stitch frame and the cam casing in section;

Fig. 3 is a fragmentary view illustrating part of the mechanism for actuating the pull-off lever;

Fig. 4 is a fragmentary sectional View illustrating the cam for actuating the pull-off;

Fig. 5 is a view of the turret with the pull-off lever mounted thereon;

Fig. 6 is a fragmentary sectional View showing the operation of the under thread pull-oil;

Fig. 7 is a side View of a portion of a buttonhole sewing machine embodying my invention and illustrating the parts in the position they have While the under thread is being pulled through the throat plate.

The buttonhole sewing machine herein illustrated has the usual work-holding means in the form of work clamps and clamp plates 2 between which the Work is clamped and which are carried by the bed plate or bed frame 4, and it also has the usual stitch-forming mechanism carried by a stitch frame 5 which is mounted to slide back and forth on the bed frame 4 in the direction of the length of the buttonhole to provide the necessary feeding movement for stitching along the sides of the buttonhole and also'to prosewing of the buttonhole, the stitch frame 5 and vide the necessary movement to carry the parts from stitching position to buttonhole-cutting position at the end of the stitching operation. Such longitudinal feeding movement is caused in the usual way by the rotation of the main cam 4| which is rotatively mounted in a cam housing 42 carried by the, stitch frame 5.

The stitch-forming mechanism comprises the usual needle 6 carried by a needle bar I mounted for reciprocation in the stitch frame 5, andalso under thread mechanism which is carried .by the rotary turret 8 that is rotatively mounted in the portion 9 of the stitch frame. The turret 8 carries. the usual throat plate H] which is provided with the sewing opening |l' through which the needle 6 operates and through which the under thread I2 is led to the work. The under thread mechanism is of the familiar type which comprises the loopers l3 and loop spreaders I4 that are mounted on an oscillating loop-carrying block l5 which is mounted to oscillate upon a stud l5. 7 V

The means for oscillating the loopers is similar to that usually employed in buttonhole sewing machines of this type. V

The looper-carrying block I5 is connected by a link I! to a hollow spindle |8 which is situated axially of the turret 8 and is given a vertical reciprocation by proper mechanism.

The loop spreaders l4 are actuated in usual way by means of a spreader wedge l9 which is mounted for oscillation on the stud l6 and is connected by a link 20 to a hollow spindle 2| that is situated co-axially of the hollow spindle I8 and is reciprocated in the direction of its length by proper mechanism.

The under thread I2 is led through the hollow spindle 2| and thence through a suitable tension device 22 mounted on the turret and thence through the eye 23 of a pull-01f lever and thence through suitable guides to one of the loopers l3 and from thence through the sewing opening ofthe throat plate I ll. 7 7

It will be understood by those familiar with buttonhole sewing machines that, during the buttonhole-cutting position illustrated in dotted lines Fig. 1 and in Fig. '7, thereby to carry the buttonhole cutter 25, which is mounted on the stitch frame, into position for cutting the buttonhole.

The buttonhole cutter is carried by the usual 7 cutter'arm 62 which is pivoted to the stitch frame 1 The stitch frame 5 and the work-holding means remain stationary during the cutting of the buttonhole slit and there is, therefore, a pause'in the relative movement between the stitch frame and the bed frame while the buttonhole slit'is being out.

tonhole-cutting position as shown in Fig. 7 the buttonhole cutter 25 is actuated by the cutter cam 6|, and the work clamps I remain closed until after the buttonhole slit has thus been out.

During this relative movement from stitching position to buttonhole-cutting position the under thread'lz and the stay cord, shown at 26, will be drawn through the throat plate It! as shown in Fig. 6 so that there will be a length of the under thread and stay cord on the under side of the work extending from the throat I0 to the last stitch of the sewed buttonhole 21. a

As stated above the present invention relates to a novel pull-off mechanism for pulling oif an additional length of under thread |2 through the throat plate after the sewing on the buttonhole has been completed and While the work is still'clamped, such pulling-off operation preferably occurring during the time that the buttonhole slit is being cut.

The under thread pull-off herein illustrated is in some respects similar to that shown in my above-mentioned Patent No. 1,905,854 but it differs from that shown in said patent in that it is actuated by a cam element carried by the main cam of the sewing machine instead of being actuated by the reverse turning movement of the turret.

The thread-pull-off which pulls the thread through the throat is in the form of a pull-ofl arm 28 which is pivotally mounted on an extension 29 of the stud l6. Said pull-off arm is provided with a. hub 30 which is journalled on said extension 29 and it is retained in position thereon by a spring retaining member 3| which is formed with a flange 32 that extends through the hub 30 into a groove 33 with which the extension 29 is provided. The upper end 34 of the pull-oil arm 28 is hook-shaped and as the pull-off is swung from the full to the dotted line position Fig.8 or toward the observer in Fig. 6 said hook-shaped end 34 will engage the portion of the under thread extending from the last stitch to the throat l0 and will thereby pull a length of under thread through the throat. The amount of thread which is thus pulled through the throat is sufficient so that when the under thread has been cut close to the work by any suitable thread-cutting device there will be projecting from the throat a sufliclent length of under thread to form properly the first stitch on the next buttonhole.

In order that the pull-off arm 28 may operate on the under thread l2 only without engaging the stay cord 26 said throat has a construction similar to that shown in Patent No. 1,941,620, January 2, 1934, in that said throat is provided with a thread-receiving groove 35 in which the under thread i2 is received during the pulling of the thread through the throat by the relative movement from stitching position to buttonholecutting position. During this movement the stay cord is retained on the upper surface of the throat and said under thread andstay cord are thus separated vertically as illustrated best in Fig. 6 with the under thread |2 occupying a position below the stay cord 26. Hence whenthe pull-off arm 28 has its operative movement it will engage the under thread only and will draw the required length thereof through the throat.

The pull-off arm'28 is normally held in its retracted position shown in full lines Fig. 3 and in Fig. 5 by means of a spring 36, one end of which is connected to the pull-off arm and the other end of which is anchored at 31 to the turret as seen in'Fig. 5. The hub 30-of the pull-off arm is provided with a stop finger 38 which by its engagement with the face 39 of the turret limits the spring-impelled movement of the pull-off arm.

The pull-01f arm 28 is given its operative movement by a pull-off cam member 40. which, is mounted on the main cam 4| by which the op.- erations of the machine are controlled.

The operative connections between, the cam 40 and the pull-off lever comprises a, lever 43 provided with ahub 44 that is journalled on a stud shaft 45 that is mounted in the portion 9 of the stitch frame. This portion of the stitch frame is hollowand comprises the two side members 46. The stud shaft 45 is mounted at its ends in the two side members 45 and spans the opening between them.

The end ll of the lever 43 extends over the edge of the main cam 4| and into position to be engaged by the upper surface of the cam 40 as the main cam rotates. This cam 40 is formed with the cam portion 48' which byits engagement with the end 4lof the lever 43 will rock the lever counter-clockwise. The lever is acted on by a return spring 49 which restores it to its initial position as soon as the end 41 has passed the cam hump 4B. The other or left hand end of the lever 43 in Fig. 1; is pivotally connected to a vertically-reciprocating plunger 50 which extends through a bearing in the upper part 51 of the portion 9 of the stitch frame. The upper end of this plunger 59 is provided with a lateral projecting finger 52 which is adapted to engage an arm 53 extending laterally from the hub 36 of the pull-off arm 28. When the lever 43' is given counter-clockwise movement by the cam projection 43 the end of said lever which is connected to the plunger 56 will be moved downwardly thereby bringing the head 52 into engagement with the arm 53. This will cause a rocking movement of the pull-off arm from the full to the dotted line position Fig. 3 thereby'performing the thread-pulling operation. As soon as the end 41 of the lever e-ahas passed over the cam hump 48 then the spring 4!} restores the lever 43 to its initial position and the spring 36 restores the pull-off arm 23 to its initial position.

The cam 48 is so positioned on the main cam 4| that it actuates the thread-pull-ofi arm 28 at the same time that the cutter cam 6| actuates the buttonhole cutter so that the pulling of the under thread through the throat It) occurs while the buttonhole slit is being out. As stated above the clamps l are still closed during the cutting of the buttonhole slit and hence the pulling of the under thread through the throat Ii) takes place before the clamps are opened.

54 indicates a stop screw carried by the portion 5| of the stitch frame and adapted to engage an arm 55 which is rigid with the lever 43 thereby limiting the spring-actuated movement of the lever 43.

The cam 48 is made with a fixed throw and in order to provide for varying the extent of the operative movement of the pull-off arm I propose to employ an adjustable connection between the lever 43- and the plunger 55. As herein shown the lower end of the plunger 59 is interiorly screw threaded and has screw-threaded engagement with a screw-thread stem 55 of a. forked connecting. member 5'! that embraces the end of the lever 43 and ispivoted thereto. This pivotal connection is through the medium of a pin 58 carried by the forked head 57. and extending,

through a slot 59 in the lever 43. By turning the plunger 50 on the screw-threaded stem 56 said plunger will be raised, or lowered. An adjustment of the plunger 50 downwardly to bring the head 52 closer to the normal or initial posi- 5 tion of the arm 53 will result in giving the pull-off arm an increased amplitude of movement while an adjustment of the plunger 5!} upwardly into a position in which the head 52 is further separated from the arm 53 when the latter is in its normal position will result in giving the pull-off arm 28 a decreased amplitude of movement. By this means it is possible to adjust the operating mechanism for the pull-off arm so as to give the latter the proper thread pulling movement to pull the desired added length of thread through the throat plate.

G4 is a lock nut on the screw-threaded stem 55 by which any desired adjustment may be maintained.

60 indicates a stay cord guide through which the stay cord 26 passes, said guide being of the familiar type which will permit the stay cord to be fed forwardly but will prevent retrograde movement thereof.

I claim:

1. In a bottonhole sewing machine, in combination, a stitch frame, a turret rotatively mounted thereon, under thread mechanism carried by the turret, a throat plate through which the thread 30 is led to the .work, a thread pull-off arm pivotally mounted on the turret and adapted to engage the under thread to pull a length thereof through the throat plate, a main cam by which the operations of the sewing machine are controlled, a 35 thread pull-off cam carried by the main cam, and operative connections between the thread-pulloff cam and the pull-off arm.

2. In a buttonhole sewing machine, in combination, a stitch frame, a turret pivotally mounted thereomunder thread mechanism carried by the turret, a throat plate through which the thread is led to the work, a thread pull-off arm pivotally mounted on the turret and adapted to: engage the under thread to pull a length thereof through the throat plate, a main cam by which the operations of the sewing machine are controlled. a

thread-pull-off cam carried by the main cam, and adjustable connections for actuating the thread-pull-off arm from the pull-off cam.

3. In a buttonhole sewing machine, in combination, a stitch frame, a turret rotatively mounted thereon, under thread mechanism carried by the turret, a throat plate through which the thread is led to the work, a thread-pull-oif arm 55 pivotally mounted on the turret and adapted to engage the under thread to pull a length thereof through the throat plate, a main cam. by which the operations of the sewing machine are controlled, a thread-pull-off cam carried by the main. cam, a lever actuated by said pull-off cam, and operative connections between said lever and said pull-off arm.

4. In, a buttonhole sewing machine, in combination, a stitch frame, a turret rotatively mounted thereon, under thread mechanism carried by the turret, a throat plate through which the un' der thread is led to the work, a thread pull-off arm pivotally mounted on the turret and adap ed toengage the under thread to pull a length thereof through the throat plate, a main cam by which the operations of the sewing machine are controlled, a thread-pulL-off cam carried by the main cam, a lever actuated by said pulleoil 75.

cam, and adjustable connections between said lever and said pull-off arm.

. 5. A buttonhole sewing machine having stitchforming mechanism, work-holding means, said stitch-forming mechanism and work-holding means having a relative movement at the completion of the sewing to carry the parts from stitching position to buttonhole-cutting position, a throat plate through which the under thread is led to the work and through which a length of under thread is drawn during the relative movement into buttonhole-cutting position, a main cam controlling the operations of the ma chine, a thread-pull-off cam carried by the main cam, and an under thread pull-off arm actuated by said thread-pull-off cam for pulling an added length of under thread through the throat plate.

6. A'buttonhole sewing machine having a stitch frame, a turret rotatively mounted thereon, stitchforming mechanism including loopers pivotally mounted on the turret, a throat plate through which the thread is led to the work, a threadpull-off arm pivoted coaxially with the loopers and adapted to engage the under thread to pull a length thereof through the throat plate, a main cam by which the operations of the machine are controlled, and means to actuate the pull-off arm from the main cam.

7 A buttonhole sewing machine having a stitch frame, a turret rotatively mounted thereon, a throat plate carried by the turret, stitch-forming mechanism including loopers pivotally mounted on the turret, a thread-pulhoif arm pivoted on the turret coaxially with the loopers and adapted to engage the thread between the throat plate and the work, a main cam by which the opera tions of the machine are controlled, and means actuated thereby to give the pull-oii arm its operative movement.

8. In a buttonhole sewing machine, in. combination, work clamps which clamp the work during the sewing and release the work at the end of the sewing, under thread mechanism, a throat plate through which the under thread is led to the work, a thread-pull-ofi arm pivotally mounted on the under thread mechanism and adapted to engage the under thread to pull a length thereof through the throat plate, and means for actuating said pull-off arm after the stitching on the buttonhole is completed but before the work is unclamped.

9. In a buttonhole sewing machine, in combination, work clamps for clamping the work, a rotary turret, under thread mechanism mounted thereon, a throat plate carried by the turret and through which the under thread is led, to the work, means to give the work clamps and the turret a relative'movernent' after the sewing on the buttonhole has been completed to bring the parts from stitching to buttonhole-cutting position, a thread-pull-off device: on the turret for pulling a length of under thread through the throat plate, and means operating independently of the rotation of the turret to actuate said pulloff device after the completion of said relative movement.

mounted :on the under thread mechanism, and

means to actuate the same to pull a, length of under thread through the throat plate while the buttonhole is being cut.

11. In abuttonhole' sewing machine, in combination, work-clamping means, a stitch frame, a

turret rotatably mounted thereon, under thread mechanism carried by the turret, a throat plate also mounted on the turret, means to give the stitch frame and work clamps a relative moveby which the operations of the sewing machine are controlled, a cutter cam mounted on the main cam for operating the buttonhole cutter; a

thread-pull-ofi cam also carried by the main cam, and operative connections between the thread-pull-oif cam and the pull-off arm to actuate the latter while the cutter cam is actuating the buttonhole cutter.

12. In a buttonhole sewing machine, in com- 7 bination, a rotary turret, under thread mechanism carried thereby, a throat plate also'carried by the turret and through which under thread is led to the work, work clamps which a clamp the work during the sewing and release the work at the end of the sewing, a main cam by which the operation of the machine is controlled, a thread-pull-off arm pivotally mounted on the turret and adapted to engage the under thread to'puli a length thereof through the throat plate, and means to actuate said pull-0f! arm after the sewing but before the work is unclamped and while the turret is at rest.

13. In a buttonhole sewing machine, in combination, work clamps for clamping the work, under thread mechanism, a throat plate through which the under thread is led to the work, means for cutting the buttonhole slit when the parts are in buttonhole-cutting position, a thread pull-0H arm and means to actuate said arm to pull a length of thread through the throat plate while the buttonhole is being cut.

14. In a buttonhole sewing machine, in combination, work clamps which clamp the work during the sewing and release the Work at the completion of the buttonhole, under thread mechanism, a throat plate through which the under thread and stay cord are led to the work, a thread pull-oft arm constructed to engage the under-thread only and to pull a length thereof through the throat plate while leavingthe stay cord undisturbed andmeans for actuating said pull-01f arm after the stitching of the buttonhole is completed. but before the work is unclamped.

15. In a buttonhole sewing machine, in combination, a stitch frame, a turret rotatively mounted thereon, under thread mechanism carried by the turret, a threat plate through which i the thread is led to the work, a thread pull-off arm adapted to engage'the under thread to pull a length thereof through the throat plate, a main cam by which the operations of the sewing machine are controlled, a thread pull-oil cam carried by the main cam and operative connections between the thread pu1l-oif cam and the pulloif arm. j

16. A buttonhole sewing machine having work-holding means, stitch-forming mechanism including under thread mechanism, a throat plate through which the under thread and stay drawn therethrough, a thread pull-off arm constructed to engage the under thread only and pull a further length thereof through the throat plate and means for actuating said pull-off arm after the stitching on the buttonhole is com- 5 pleted but before the work is unolamped.

CARL A. O. GRIP. 

